Single tenant in building pursuing Core & Shell

The building is pursuing C&S certification and has a perspective tenant that may fit out the entire space. We are proposing to charge the perspective tenant the entire electricity bill minus the proration of the core and shell floor area. For example: building = 100,000 sf Core & Shell = 10,000 sf Tenant space = 90,000sf electricity paid for by the tenant to be (90,000/100,000) x entire bill. We plan to install a centrally monitored electronic metering network, detailed guidelines to tenant, clear guidelines for tenant sub-metering per LEED CI, and corrective action strategy. Our difficulty is determining if we need sub-meters for a building that may become a single tenant. thank you.